This is probably not what the therapist would tell you to do, but be assertive. I have a verbally abusive and drunken father that my mother copes with, and now I just tell them plainly to divorce and move on. I went through remembering the abuse of my father to me and my mother when my sisters left the house for college and everything else and it was bad. It was a house full of tension and probably is what caused my schizophrenia. I still find myself rebelling to his ways, and for me right now, wouldn't attend his funeral because he is just the self-righteous type that admits no wrong, so what is the point. His ears are blocked up and the past years I have limited my relationship to a minimum like he is already developing dimensia and just telling him white lies when I visit my mother to maybe make him realize he has problems with his own mental health.

That is my story about my abusive father, but one day when I have the courage I want to say you are a bad father, grandfather and I'm not hanging around to see you change, and I don't care what happens anymore.

Point being be in control, assertive, and positive, and just move on from the experience.